1. Field of the Invention
The present invention relates to novel aqueous solutions or aqueous dispersions of copolymers. The invention furthermore relates to the use of these aqueous solutions or dispersions for the fatliquoring or filling of leather and fur skins.
2. Discussion of the Background
DE-A 39 26 167 (1) discloses the use of copolymers which are obtainable by free-radical copolymerization of C.sub.8 -C.sub.40 -monoolefins with ethylenically unsaturated C.sub.4 -C.sub.8 -dicarboxylic anhydrides in the manner of a bulk polymerization at 80 to 300.degree. C. to give copolymers with molecular weights of from 500 to 20,000, subsequent solvolysis of the anhydride groups of the copolymers and at least partial neutralization, in aqueous medium with bases, of the carboxyl groups produced in the solvolysis, and which are in the form of aqueous solutions or dispersions, for the water-repellent treatment of leather and fur skins.
DE-A 39 26 168 (2) discloses the use of copolymers which are obtainable by free-radical polymerization of C.sub.8 -C.sub.40 -alkyl vinyl ethers or mixtures of C.sub.8 -C.sub.40 -alkyl vinyl ethers and up to 50 mol % of C.sub.8 -C.sub.40 -monoolefins with ethylenically unsaturated C.sub.4 -C.sub.8 -dicarboxylic anhydrides to give copolymers with molecular weights of 500 to 20,000, subsequent solvolysis of the anhydride groups of the copolymers and at least partial neutralization, in aqueous medium with bases, of the carboxyl groups produced in the solvolysis, and which are in the form of aqueous solutions or dispersions, for the water-repellent treatment of leather and fur skins.
DE-A 39 31 039 (3) discloses the use of copolymers which contain as copolymerized units 50 to 90% by weight of C.sub.8 -C.sub.40 -alkyl (meth)acrylates and/or vinyl esters of C.sub.8 -C.sub.40 -carboxylic acids and 10 to 50% by weight of monoethylenically unsaturated C.sub.3 -C.sub.12 -carboxylic acids, monoethylenically unsaturated C4-C.sub.12 -dicarboxylic anhydrides and/or derivatives thereof, and which have molecular weights of 500 to 30,000, in at least partially neutralized form in aqueous solution or dispersions for the water-repellent treatment of leather and fur skins.
The water repellents for leather containing the copolymers from publications (1) to (3) are free of additional emulsifiers. Besides the water-repellent action, these compositions additionally have a certain fatliquoring and retanning action.
EP-A 372 746 (4) describes aqueous dispersions of water-insoluble amphiphilic copolymers as auxiliaries for the treatment of tanned leather. These amphiphilic copolymers are composed of a larger proportion of a hydrophobic monomer, for example long-chain alkyl (meth)acrylates, primary alkenes or vinyl esters of long-chain alkylcarboxylic acids, and a smaller proportion of a hydrophilic monomer, for example (meth)acrylic acid, maleic acid and their anhydrides. The compositions are used to improve the water resistance of the leather. The dispersions are used without additional emulsifiers.
DE-C 26 29 748 (5) discloses the use of copolymers of C.sub.10 -C.sub.30 -olefins and maleic anhydride, which are hydrolyzed with alkali metal bases or amines, for the filling and fatliquoring of leather and fur skins. The hydrolyzed copolymers may also be reacted with alkali metal bisulfite. Since the copolymers are prepared in organic solvents, and the latter are not removed, the aqueous copolymer dispersions prepared therefrom contain considerable amounts of organic solvents, for example xylene or dodecylbenzene.